Spectroscopy of the bright optical counterparts of X-ray sources in the direction of M 31
University of Crete, Department of Physics, PO Box 2208, 71003, Heraklion, Greece e-mail: firstname.lastname@example.org
2 IESL, Foundation for Research and Technology, 71110, Heraklion, Greece
3 Max-Planck-Institut für extraterrestrische Physik, 85741 Garching, Germany
Accepted: 17 July 2009
Context. A recent survey of the Local Group spiral galaxy M 31 with XMM-Newton yielded a large number of X-ray sources.
Aims. This is the second in a series of papers with the aim of identifying the optical counterparts of these X-ray sources.
Methods. We have obtained optical spectra for 21 bright optical counterparts of 20 X-ray sources in the direction of M 31, using the 1.3-m Skinakas telescope in Crete, Greece.
Results. For 17 of the 20 X-ray sources, we have identified the optical counterpart as a normal late type star (of type F or later) in the foreground (i.e. in the Milky Way). For two more sources, there were two possible optical counterparts, in each case, while two more objects have X-ray properties that are not compatible with the spectral characteristics of late type non-flaring stars.
Key words: galaxies: individual: M 31 / X-rays: galaxies / X-rays: stars
© ESO, 2009